using grep --perl-regexp this is a sample output of `ls` $ ls -lAF -rw------- 1 martin martin 168 Jan 25 23:26 aaa -rw------- 1 martin martin 168 Jan 25 23:26 bbb -rw------- 1 martin martin 168 Jan 25 23:26 ccc I would like to colorize the `user` and `group` entries. However, my syntax only colorizes `user`,but not the `group`: ls -lAF | grep --color -P '^\S+\s+\S+\s+\K\S+' I don't understand what the `\K` exactly means. How could I match both `martin martin` in my sample output?

`\K` marks the start of the region to color.

See `man pcrepattern` for details.

> The escape sequence `\K` causes any previously matched characters not to be included in the final matched sequence.

That means you need:


ls -lAF | grep --color -P '^\S+\s+\S+\s+\K\S+\s+\S+'